Control of Multidrug Transport Activity in Embryos

本研究的两个主要目标是：第一，了解多药外排的细胞生物学调节 第二，探讨这些转运蛋白在胚胎发育过程中的保护和调控作用。 发展这一建议将两个知识体系联系起来，一个是关于细胞生理学， 多药外排转运，主要在癌症和上皮转运的背景下进行检查，另一个 关注胚胎发育过程中细胞表面和膜组织的结构变化。在 ROO阶段的这一建议，哈姆敦将继续和扩大他之间的关系调查 早期胚胎发育中细胞表面的变化和外排转运蛋白活性的变化， 海胆作为一个容易分析和操纵的模式生物。他还将继续努力，目前 在该奖项的K阶段正在进行，将海胆的发现转化为小鼠模型，以便 表征这些活性变化在保护胚胎免受潜在致畸剂影响中的作用 在辅助生殖过程中。该奖项K阶段的研究显示， 海胆卵受精后ABCB（pgp）和ABCC（mrp）外排转运蛋白活性 然后在4个胚胎生殖系祖细胞的亚群中， 就像微小的微粒。在大多数其他系统中，ABC转运蛋白进出膜的循环是连续的，而在海胆中，外排活性和皮质组织的两次快速变化为研究细胞结构和转运蛋白功能关系提供了一个强大的模型。在目标1和2中，Hamdoun将通过转运蛋白向微绒毛尖端的移动来表征Sp-ABCB 1a（哺乳动物p-gp的直系同源物）活性的受精后再分布。在第三个目标中，Hamdoun将把这些发现扩展到小鼠模型，特别是他对小鼠卵母细胞受精后pgp转运蛋白活性丧失的初步发现的后续研究，他将再次关注活性变化如何与皮质肌动蛋白细胞骨架的组织相关。在新的第四个目标中，Hamdoun将研究小微粒中转运蛋白调节的机制。

The two main goals of this research are first, to understand the cell biological regulation of multidrug efflux transport and second, to probe the roles of these transporters in protection and regulation of embryonic development. This proposal links between two bodies of knowledge, one on the cellular physiology of multidrug efflux transport, primarily examined in the context of cancer and epithelial transport, and another focusing the structural changes in cell surface and membrane organization of embryo development. In the ROO Phase of this proposal, Hamdoun will continue and expand his investigation ofthe relationship between cell surface changes in early embryo development and changes in the efflux transporter activity focusing on sea urchins as an easily assayed and manipulated model organism. He will also continue efforts, currently ongoing in the K Phase of this award, to translate findings from the sea urchin to the mouse model, in order to characterize the role of these activity changes in protection of the embryo from potential teratogens encountered during assisted reproduction. Research in the K Phase of this award has revealed rapid upregulation of ABCB (pgp) and ABCC (mrp) efflux transporter activity following fertilization of sea urchin eggs and then later down-regualtion of efflux transport In a subset of 4 embryonic germline progenitor cells, known as the small micromeres. In most other systems, cycling of ABC transporters in and out of membranes is continuous, whereas in the sea urchin the two episodes of rapid change in efflux activity and cortical organization provide a powerful model for studying the cell structure and transporter function relationships. In Aims 1 and 2 Hamdoun will characterize the post-fertilization redistribution of Sp-ABCB1a (an ortholog of mammalian p-gp) activity by movement of the transporter to the tips of microvilli. In the third Aim, Hamdoun will extend these findings to the mouse model, specifically following up on his preliminary finding of loss of pgp transporter activity after fertilization of mouse oocytes and again he will focus on how activity changes relate to organization ofthe cortical actin cytoskeleton. In a new fourth Aim, Hamdoun will study the mechansims of transporter regulation in the small micromeres.